Seev 800 Battery Replacement Options

I have a SEEV 800 fat tire scooter. Original Battery pack would die after driving a block. Opened it up, the pouches are a little swollen. The original SEEV 800 batteries are a whopping $550... if you can find a replacement (I am currently calling and emailing around)

The Battery Pack is 60V 30A Max 12ah (with a 30 amp fuse)

I thought I would be cute and buy two GreenWorks 60v 5ah and run them in parallel. I printed up two amazing slide in cases for the batterys and when I went to test it... there was too much voltage sag. I put a meter on it, and it would get up to 24.9a MAX but it just wouldn't take off my my big butt on it. I am now down $260 for those two batterys My fault I know. I should have done better math or asked here first!

I am wondering if I went with the Greenworks or Kolbalt 80v , I think that has max amps of 30amps - I am wondering if the controller can handled the extra 20v?

Main Technical Parameters of the Controller
1. Current limiting protection value: ≤25±1A
2. Under voltage protection value: 52±0.5V

Thanks in advance! Love this site!

Scott aka KozmoK

KozmoK said:

I have a SEEV 800 fat tire scooter. Original Battery pack would die after driving a block. Opened it up, the pouches are a little swollen. The original SEEV 800 batteries are a whopping $550... if you can find a replacement (I am currently calling and emailing around)

The Battery Pack is 60V 30A Max 12ah (with a 30 amp fuse)

I thought I would be cute and buy two GreenWorks 60v 5ah and run them in parallel. I printed up two amazing slide in cases for the batterys and when I went to test it... there was too much voltage sag. I put a meter on it, and it would get up to 24.9a MAX but it just wouldn't take off my my big butt on it. I am now down $260 for those two batterys My fault I know. I should have done better math or asked here first!

I am wondering if I went with the Greenworks or Kolbalt 80v , I think that has max amps of 30amps - I am wondering if the controller can handled the extra 20v?

Click to expand...

It might, but I wouldn't count on it. There are a number of parts that may only handle slightly above the original max voltage.

Additionally, "80v" is probably not the max full charge voltage of those toolpacks, so they may be even higher at full charge. How much higher, I don't know; there is probably a thread around here with that info with all the tool-pack operated bikes/etc people have made.

However: if the original battery is "60v" then that is probably really a nominal voltage, not full charge. Which chemistry is it? LiFePO4, or something else? (if it doesn't say, dont' worry).

Typically a 60v battery for Li-ion is 16s, and would really be 59.2v nominal, assuming 3.7v/cell. If it's 4.2v/cell full, that times 16s is 67.2v.

Most of the parts that can handle that voltage can probably handle whatever voltage the "80v" pack is when it's full, too, but not guaranteed, especially with the converter from battery voltage to the low voltages (12v and 5v) the controller brain, hall sensors, display, throttle, etc. run off of.

Main Technical Parameters of the Controller
1. Current limiting protection value: ≤25±1A
2. Under voltage protection value: 52±0.5V

Click to expand...

Number 1 means that you need a battery that can handle *at least* 25A continous; assume 30A+ for a small safety margin. Some batteries have a listing for their max and their continous amps, some only list one and that's probably their max for short bursts (becuase marketing people like bigger numbers; it sells more stuff even if it's a lie). If there is only one number, you may want to cut it in half for continous use, for safety margin.

Number 2 means that you need a battery that has most of it's capacity above 52v. So a "60v" 16s Li-Ion, for instance, at 52v would be at only 3.25v/cell, which is pretty well empty. An 18s at 52v would be 2.89v/cell which is very dead. A 14s at 52v is only about half empty at 3.7v/cell.